Radon gas, of great concern to American home buyers and home owners, is virtually unknown to Canadians. While the world considers radon gas an indoor health hazzard, Canada continues to view this silent killer as a relatively-benign intruder. This ordourless, tasteless, invisible gas is the second major source of lung cancer.

While radon is estimated to cause between 7,000 and 30,000 deaths per year in the US, the Canadian government maintains that radon deaths cannot be proven in Canada.

Radon is a radioactive gas formed by the natural breakdown of uranium in soil, rock and water. In a few areas, large amounts of radon can dissolve in groundwater and then be released when that water is used in household activities like showering, cooking and washing. Building materials are not typically a significant source of radon. Radon decays to form other radioactive elements called "daughters of radon." Radon gas and these particles are inhaled and become lodged in the lungs where they can penetrate lung tissue causing lung cancer.

Radon usually escapes from the ground into the outdoor air where it is diluted to harmless concentrations. Problems arise when radon is trapped in an enclosed space like a house where it accumulates to high levels.

According to the Radiation Safety Institute of Canada, a non-governmental agency providing radiation safety and testing services, radon is present in the air of almost every home and building in Canada.

Since this invisible gas cannot be detected without specific measuring equipment and does not cause visible symptoms like headaches and coughs, there is nothing to alert you to the presence of this gas in your home, workplace or children's schools.

In the mid-1970's, Health Canada surveyed 14,000 homes in 18 cities across Canada and reported low concentrations in the majority of homes, but noted high levels in a small but significant number of homes in some cities. The government does only limited radon testing in schools and workplaces since it expects levels lower than those found in homes.

Natural Resources Canada has studied radon and related problems in Nova Scotia, Quebec and other parts of Canada looking for effective predictive and measurement techniques. As yet, there is no large-scale technique for determining home levels. The age of the home is not considered a reliable prediction factor. Similar homes, even neighbouring houses, may have very different gas levels. Soil characteristics, construction type, foundation condition and efficiency of ventilation systems are only a few of the many factors involved. The only way to know the radon level in your home is to test for it. If high levels are discovered and you're on well water, a radon water test may be advisable.

The government has placed all the responsibility squarely on your shoulders. No regulation dictates acceptable radon levels and enforces remedies. According to Health Canada and the Canada Mortgage and Housing Corporation (CMHC), "It is the choice of each homeowner to determine what level of radon exposure they are willing to accept." The government does recommended that "remedial measures be taken where the level of radon in a home is found to exceed 22 pCi/L ( 800 Bq/m3) as the annual average concentration in the normal living area." In contrast, the World Health Organization recommends action if radon levels are 4 pCi/L (150 Bq/m3) or higher and suggests reducing levels below this since risks continue to exist. Most homes can be reduced to about 2 pCi/L or less.

Costs for lowering the level of radon gas range from a few hundred dollars to about three thousand dollars. Repairs and renovations that reduce moulds, dampness, drafts, termite invasion and odours in your basement will also lower radon levels. Talk to professionals, including your real estate broker and your home inspector, about radon testing for the new or resale home you're buying or your current home. "Radon: A guide for Canadian homeowners", a free PDF publication published by Health Canada and CMHC, explains the "how to" behind measuring and reducing radon levels. Analysis costs start at about CN$20 to CN$40 with do-it-yourself kits. When high levels exist, contact a trained radon reduction contractor to correct the problem. For details on new-construction radon reduction techniques, contact your local building inspector.

Direct your health questions to the Radiation Protection Branch of Health Canada at www.hc-sc.gc.ca or 613-954–6671. At the provincial level, contact the Ministry of Health e.g. British Columbia or Ministry of Labour.

Canadians have long expected the government to keep them safe, but disasters like Walkerton increasingly force us to face our individual responsible for preserving health and well-being. You spend between 70 and 90 per cent of your life breathing indoor air. Do you want to trust your future to Canadian radon safety levels set 550% higher than the rest of the world?

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